Lead-free ZnO added K0.5Na0.5NbO3 piezoelectric ceramics have been prepared by a conventional solid state process. The XRD results show that all the K0.5Na0.5NbO3 ceramics with various ZnO contents are single phase with an orthorhombic perovskite structure. The bulk density obtained by the Archimedes method indicates that the addition of ZnO improves the density of K0.5Na0.5NbO3 ceramics under the same sintering conditions. Especially, at a level of 1 mol% ZnO, the sample sintered at 1100 oC for 1h exhibits the highest bulk density (ρ = 4.28 g/cm3) and shows optimal piezoelectric properties, d33 = 135 pC/N and kp = 0.40.

Keywords: Lead-free piezoelectric, K0.5Na0.5NbO3, ZnO, Microstructure.